timing in physics simulations: per scene or per object?
Different simulations can run at different speeds, there is no one &quot;master clock&quot;, which is a good thing, because you can control separately the speed of your simulations.
For rigid bodies, the speed setting is under Properties Editor/Scene/Rigid Body World
Similarly, soft bodies and cloth have a speed setting under the Physics tab. For fluids and smoke you set the simulation speed in their domain objects, also under the the Physics tab. For fluid simulations, also see the question For Fluid Simulation, what do the Start, End and Speed settings mean?
Dynamic Paint canvases where the surface type is Waves have two speed settings:

Timescale Directly adjusts simulation speed without affecting simulation outcome. Lower values make simulation go slower and otherwise.
Speed Affects how fast waves travel on the surface. This setting is also corresponds to the size of the simulation. Half the speed equals surface double as large.